Demagnetizing effects and correction in permeameter measurements of soft magnetic cylinders

Du Xing Chen

    Research output: Contribution to journalArticleResearch

    1 Citation (Scopus)


    © 1965-2012 IEEE. The demagnetizing field Hd produced by local magnetic poles around the ends of soft magnetic cylinders magnetized in International Electrotechnical Commission type-B permeameter is studied experimentally along the major hysteresis loop M(H). The usual relation of Hd=-NpM is shown to be valid with a positive demagnetizing factor Np < 0.0003, but at H∼± HcJ, the intrinsic coercivity, the action of Hd is anomalously characterized by an oscillation of Np from -∞ to ∞ at H=± HcJ with increasing |H|, owing to a local decrease of differential reluctance in the cylinder around where the maximum differential susceptibility occurs. These unusual demagnetizing effects make the M(H) measured at high |H| be rather accurate with often presented significant error at H∼ ± HcJ. Having an over-large measured HcJ, this error is systematic, and it may be corrected with a shift in HcJ and a residual demagnetizing factor Δ Np < 0.0001, if compared to demagnetizing corrected solenoid measurements of the same cylinders of large length-to-diameter ratio.
    Original languageEnglish
    Article number8666163
    JournalIEEE Transactions on Magnetics
    Publication statusPublished - 1 May 2019


    • Demagnetizing factor
    • ferromagnetic cylinders
    • permeameter


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